Arginine and melatonin are different compounds with different affects on the body, yet their paths meet continually in the cause or treatment of disease. The medicinal synchronicity these two substances create could -- in the hands of a knowledgeable medical professional -- lead to the treatment of serious and even life-threatening diseases. Talk with your physician if you are considering taking arginine or melatonin supplements alone or together to treat a medical condition.
Melatonin and Arginine
Melatonin is a naturally occurring hormone that regulates your wake and sleep cycle. Melatonin is produced mainly in the pineal gland located in the brain. Your body makes melatonin using the amino acid tryptophan as one ingredient.
Arginine is an amino acid. Usually, your body can synthesize all the arginine it needs. At times, however, your body needs to get more arginine from your diet -- from red meat, chicken, fish, milk products and cheese. Arginine is used to build proteins, create the blood vessel relaxant nitric oxide and repair damaged tissue.
Strokes result from brain tissue damage caused by a lack of blood flow or from blood spilling onto brain cells from a burst blood vessel. Studies relating arginine and melatonin to strokes seem contradictory. Melatonin limits stroke damage with its antioxidant property. It also increases the amount of the enzyme that eliminates arginine in the brain. A 2011 study published in the "Journal of Pineal Research" provided evidence that melatonin protected brain tissue in rats with induced strokes. On the other hand, a 2008 study with human subjects published in "Clinical Neurology" showed that arginine improved stroke symptoms by dilating blood vessels in the brain through increased nitric oxide levels.
Arginine and melatonin together may help promote heart muscle health. Melatonin can protect the heart from free radical damage through its antioxidant properties. A "Journal of Hypertension" study published in 2009 examined the effect of melatonin on rats given a substance known to increase blood pressure and cause fibrous tissue to form in the heart. The researchers found melatonin prevented fibrous growth and protected the rat heart for nitric oxide damage. Arginine protects the heart by lowering blood pressure and decreasing the fluid load in congestive heart failure patients.
Both melatonin and arginine contribute to the cascade of processes involved in penile erection. Arginine works by contributing to nitric oxide production. Nitric oxide in turn promotes erections primarily through vasodilation and increased penile blood flow. Melatonin promotes erectile function by acting on the brain. A 2000 animal study published in "Brain Research" looked at the effect of large doses of melatonin on male rat sexuality. The researchers concluded that melatonin acted upon serotonin and melatonin receptors in the rats' brain to restore sexual competence.